Chelicerata - Encyclopedia.com
2018年6月27日 · Chelicerata A phylum of invertebrate animals that includes arthropods belonging to the classes Arachnida (spiders and scorpions), Merostomata (horseshoe crabs), and Pycnogonida (sea spiders). The body of these animals is divided into an anterior prosoma and a posterior opisthosoma and bears six pairs of appendages, typically comprising chelicerae, …
Sea Spiders - Encyclopedia.com
2018年5月18日 · Pycnogonida (Pantopoda; sea spiders; phylum Arthropoda, subphylum Chelicerata) A class of marine chelicerates, all of which are small (total body length usually 1–10 mm but up to 6 cm in some species, with a leg span of 75 cm). The narrow body comprises a cephalon and four–six distinct segments, the cephalon bearing a proboscis. The posterior part …
Merostomata (Horseshoe Crabs) - Encyclopedia.com
Merostomata (Horseshoe crabs) Phylum Arthropoda Class Chelicerata Subclass Merostomata Number of families 1 Thumbnail description Marine creatures distinguished by a large, hard exoskeleton that includes an arched, horseshoe-shaped shield in front (prosoma), a middle portion (opisthosoma), and a thin tail (telson); they are among the oldest living organisms
Arachnida (Spiders, Scorpions, Mites, and Ticks) - Encyclopedia.com
Arachnida (Spiders, scorpions, mites, and ticks) Phylum Arthropida Class Chelicerata Subclass Arachnida Number of families 648 Thumbnail description Highly recognizable and populous eight-legged invertebrates with two body parts (a prosoma and an abdomen), pedipalps, book lungs or tracheae, sometimes poisonous fangs, and generally the ability to produce silk; they are …
telson - Encyclopedia.com
2018年5月8日 · telson The spike-like, terminal segment of the opisthosoma that occurs in certain chelicerates (Chelicerata), e.g. limulids and eurypterids. The prominent, backward-pointing spine at or near the rear extremity of a trilobite (Trilobita) is also called a telson, although it may or may not be the equivalent of a true telson.
pseudoscorpions - Encyclopedia.com
2018年5月29日 · Pseudoscorpiones (pseudoscorpions; subphylum Chelicerata, class Arachnida) Order of minute arachnids whose name refers to their large, scorpion-like, chelate pedipalps which do not, however, possess a stinging organ. Pseudoscorpions are flattened, with the oval opisthosoma joined broadly to the prosoma. Most are black, brown, or brownish-green, and …
Arachnids | Encyclopedia.com
2018年6月8日 · Arachnids are members of the subphylum Chelicerata, which also includes the phylogenetically-related (related by evolution) ancient horseshoe crabs. Like other arthropods, arachnids have paired, jointed appendages, a hardened exoskeleton, segmented body, and well developed head.
cephalothorax - Encyclopedia.com
2018年5月29日 · cephalothorax In some members of the phylum Arthropoda, the fused head and thorax. It is found in members of the Chelicerata (classes Merostomata, Arachnida, and Pycnogonida), and in most Crustacea. In spiders, it is the prosoma, which is covered by a sclerotized plate (carapace), and which bears the walking limbs, pedipalps, chelicerae, and …
Arthropoda - Encyclopedia.com
2018年5月23日 · Arthropoda [1] The phylum Arthropoda is the largest and most varied in the animal kingdom. It includes well over one million described species. This represents approximately three-quarters of all known biological organisms, living or extinct.
Pycnogonida (Sea Spiders) - Encyclopedia.com
Pycnogonida (Sea spiders) Phylum ArthropodaClass PycnogonidaNumber of families 8Thumbnail description Spiderlike marine creatures that both live on and eat seaweed and some marine invertebrates Source for information on Pycnogonida (Sea Spiders): Grzimek's Animal Life Encyclopedia dictionary.